Electrode holder for high temperature heating apparatus furnace



y 1955 B. MATCHEN 3,249,675

ELECTRODE HOLDER FOR HIGH TEMPERATURE HEATING APPARATUS FURNACE Filed 001;. 4:, 1963 INVENTOR. [F 2 BEN MATCHEN United States Patent ELECTRODE HOLDER FOR HIGH TEMPERATURE HEATING APPARATUS FURNACE Ben Matchen, Niagara Falls, Ontario, Canada, assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Filed Oct. 4, 1963, Ser. No. 314,020 3 Claims. (Cl. 13-25) The invention relates to a holder or clamp for electrical resistance elements used in high temperature heating apparatus, such as electric tunnel kilns and furnaces. The invention is an improvement on a similar invention and copending application of a colleague, George R. Watson, Serial No. 152,125, filed November 7, 1961.

Because of the continuous service and the high temperatures electric kilns and furnaces are required to maintain today, it has become necessary to provide a suitable holder or clamp for electrical heating elements which are uniformly cooled, maintain good electrical contact with the electrode, prevent hot gases from escaping, and which enable the electrode to be easily and rapidly replaced when necessary.

Heretofore, holders or clamps of this type have'not been known to exist in any form let alone be commercially available. I

Therefore, it is one object of this invention to provide an improved holder or clamp of the nature above men-.

tioned, which is capable of operating at high temperatures.

Another object is to provide such a holder that is gas tight.

Yet another object is to provide an electrode holder which enables an electrode to be changed easily or replaced rapidly.

Still another object is to provide a heating element clamp which provides a large area of contact with the electrode. 4

A further object is to provide a clamp which is uniformly cooled.

r A further object yet is to provide an electrode holder which can be tightened easily or loosened about an electrode.

A still further object is to provide an electrode holder which automatically positions and centers the electrode.

Other objects will be obvious to those of ordinary skill in the art upon reading this disclosure, while some are pointed out hereinafter in the following description, claims, and-in the accompanying drawings illustrating one of many possible embodiments of the invention in which: v

1 FIGURE 1 is avertical cross section through the electrode holder .of the instant invention, taken approximately on line 11 ofFIGURE 2, and

FIGURE 2 is a-fragmentary side elevation of the electrode holder attached to a portion of a kiln or furnace.

One example of a kiln or furnace in which the instant invention could be utilized is shown in a US. Patent 2,534,518 to George N. Jeppson. In a kiln of this type the long heating element or electrode has to be supported on both ends, and therefore, a holder or clamp in acconducting material having an extended portion 12 integral with a rectangular mounting flange 14. There are four holes 16 in flange 14, accommodating respective bolts 18 with nuts 19 for fastening the body to an electrical insulating member 20, which, in turn, is attached to the metal shell 23 of the kiln or heating apparatus 22 by bolt and nut assemblies 24. However, the

insulating member in some instances could be eliminated by anchoring the bolts 18 of longer length in the insulating refractory 26 of the kiln itself. The body 10 may then be mounted directly against the refractory material 26 by providing a larger opening through the metal shell 23 of the kiln 22. Another alternative is to substitute for the metal shell an electrical insulating material,- such as transite, in the firing zone, only.

-The electrical insulating member 20 has a thick portion 28 with a hole or bore 30 through it, and is aligned with a bore 32 in the refractory material 26. A heating element or electrode 34 of smaller size is inserted in the bores 30 and 32 and may extend through identical bores at the opposite side of the kiln, supported at the 7 tight by providing suitable sealer or gasket (not shown),

or the member 20 may be resilient enough to prevent gas leakage on compression by itself. I

Preferably the extended portion 12 of the hollow body 10 has an uninterrupted internal tapered or camming surface 36 which is engaged by a mating tapered surface 38 of a hollow deformable collet or sleeve 40 made of an electrical conducting material, having an internal surface for mating and engaging the external surface of an electrode. The external surface at the ends of the electrode are usually straight or slightly tapered, but whatever the shape, the internal surface of the collet should correspond to and mate properly with the shape of the electrode. The collet 40 preferably has a plurality of spaced slots 42 through its wall extending from either end for more than half its length providing spaced portions for clamping about the heating element or electrode 34.

Attached by screws 44 to the end of slotted collet 40 is a cover or cap 46 with a centrally positioned spherical shaped T slot 48 engaged by a similarly shaped head of a rotatable screw 50 fixed to a hand wheel 52. It can be seen that the connection provides free rotating movement between the collet 40 and cap 46 but positive axial displacement of the collet 40 when the screw 50 is rotated. The screw 50 engages a central threaded hole 54 in a slotted cover or nut 56 attached to the cylindrical portion by a plurality of eye bolts 58 and wing nuts 60.

as electrically insulated tubing. The outlet 72 may be connected by a suitable conduit to a drain or to a recooling and recirculating system.

Integral with the body or housing 10 is a portion 74 with a plurality of holes 75 through it for attaching an electrical conductor 76 or conductors thereon for supplying electric current to the heating electrode 34.

Operation It can be seen that when an electrode 34 has to be removed or replaced, the screw 50 is rotated and moved a very short distance, enough to remove the clamping pressure against the wing nuts 60 and between the electrode'34' and collet 40.

The wing nuts 60 are then loosened sufficiently to enable the eye bolts 58 and wing nuts 60 to be swung out of the way. Now the whole assembly, including the handle 52, screw 50, cover 56, cap 46, and collet 40, is easily and quickly removed as a unit leaving plenty of room' for removing the electrode 34. It is to be understood that if the electrode is still in one piece, the opposite holder, if one is used, also must be conditioned in the same way described above before the electrode can be removed. If it is broken, a section is removed through each holder.

As shown in FIGURE 1, the electrode 34 may be provided at its ends with a threaded portion 78 into which may be screwed a threaded electrode removing tool not shown. In that manner, the electrode may be removed and a new one inserted into bore 30. Before it is fully inserted, the deformable tapered slotted collet 40 and associated parts are attached to the end of the electrode 34 after which it is inserted further into body 10. The eye bolts 58 and wing nuts 60 are then swung.

thereby automatically centering the electrode 34 in the bores 30 and 32 and contracting the collet 40 to clamp tightly about the electrode 34. Likewise the other end of the electrode may be treated in the same manner described, if necessary.

If necessary to prevent accidental electrical shock, cover 46, eye bolts 58, handle 54 and any other part desired may be made of any electrical insulating suitable such as transite. The only members which must be made of electrical conducting material, such as copper or alloys thereof, are the hollow body and deformable collet 40.

It has been shown that there has been provided by this invention a practical and easily manipulated electrode holder, that is quickly released or tightened, gas tight, provides a large area of positive electrical contact about the electrode and which automatically centers the electrode within the opening in the kiln or furnace.

As many possible embodiments and changes may be made of the above invention, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. An electrode holder for mounting on electrically heated furnaces or kilns comprising:

a hollow electrically conducting housing having a passage for conveying a cooling medium therethrough,

a tapered surface internally of said housing,

a hollow electrically conducting deformable collet having an external surface for mating engagement with said tapered surface and an internal surface for mating engagement with the external surface of a portion of an electrode,

adjustable means supported by said housing to move said deform-able collet into and out of wedging en-' gagement with said tapered surface respectively to the electrode, and pivotal meanson said housing including a fastener to remove and secure said adjustable means and said collet from and to said housing as a unit.

2. An electrode holder for mounting on electrically heated furnaces or kilns comprising:

a hollow electrically conducting housing,

an uninterrupted tapered surface internally of said housing,

an electrically conducting contractable sleeve having an external surface for mating engagement with said uninterrupted tapered surface and an internal surface for mating, engagement with the external surface of a portion of an electrode,

screw means including a removable cover supported by said housing to force said contractable sleeve between said uninterrupted tapered surface and an electrode to clamp the electrode within the sleeve,

means on said housing to remove or secure sa'id screw means and said collet including said removable cover from or to said housing as a unit, and

means between said removable cover preventing gas leakage therethrough.

3. An electrode holder for mounting on electrically heated furnaces or kilns comprising:

a hollow electrically conducting housing,

means including a flange to make a gas tight mounting between said housing and kiln,

a circular inclined surface internally of said housing,

means for attaching at least one electrical conductor on said housing,

a hollow electrically conducting slotted deformable collet having an external surface for mating engagement with said circular inclined surface and an internal surface for mating engagement with the peripheral surface of a portion of an electrode, I

adjustable means including a housing cover supported by said housing to move said slotted collet into or out of. wedging engagement with said circular inclined surface to increase or decrease the clamping pressure about the electrode,

a. freely rotatable but positive axial displacing connection between said adjustable means and said slotted collet, and

means on said housing, to remove or secure said adjustable means, said housing cover, and said slotted collet from or to said housing as a unit.

References Cited by the Examiner UNITED STATES PATENTS 1,133,259 3/1915- Brown 13-25 1,157,819' 10/1915 Stassano 13-25 X 1,363,815 12/1920 Saklatwalla et al. 13-16 1,453,398 5/ 1923 Little 13-25 1,710,416 4/ 1929- Goeller 339270 X 2,104,555 1/ 1938 Cousteix 13-25 X 2,447,254 8/ 1948 Jorgensen 339270 X FOREIGN PATENTS 442,169 2/ 1936 Great Britain. 15,269 2/ 1927 Netherlands.

RICHARD M. WOOD, Primary Examiner.

ANTHONY BARTIS, Examiner. V. Y, MAYEWSKY, Assisrant'Examiner. 

1. AN ELECTRODE HOLDER FOR MOUNTING ON ELECTRICALLY HEATED FURNACES OR KILNS COMPRISING: A HOLLOW ELECTRICALLY CONDUCTING HOUSING HAVING A PASSAGE FOR CONVEYING A COOLING MEDIUM THERETHROUGH, A TAPERED SURFACE INTERNALLY OF SAID HOUSING, A HOLLOW ELECTRICALLY CONDUCTING DEFORMABLE COLLET HAVING AN EXTERNAL SURFACE FOR MATING ENGAGEMENT WITH SAID TAPERED SURFACE AND AN INTERNAL SURFACE FOR MATING ENGAGEMENT WITH THE EXTERNAL SURFACE OF A PORTION OF AN ELECTRODE, ADJUSTABLE MEANS SUPPORTED BY SAID HOUSING TO MOVE SAID DEFORMABLE COLLET INTO AND OUT OF WEDGING ENGAGEMENT WITH SAID TAPERED SURFACE RESPECTIVELY TO INCREASE AND DECREASE THE CLAMPING PRESSURE ABOUT THE ELECTRODE, AND PIVOTAL MEANS ON SAID HOUSING INCLUDING A FASTENER TO REMOVE AND SECURE SAID ADJUSTABLE MEANS AND SAID COLLET FROM AND TO SAID HOUSING AS A UNIT. 